<template>
  <div>
    <!-- 无id时, 可以使用index(反正也是就地更新) -->
    <div style="display: inline-block" v-for="(item ,index) in arr" :key="index">
      <input type="checkbox" v-model="list" :value="item" />
      <span>{{item}}</span>
    </div>
    <p>你选中的元素, 累加的值和为:{{sum}} </p>
  </div>
</template>

<script>
  export default {
    data() {
      return {
        arr: [9, 15, 19, 25, 29, 31, 48, 57, 62, 79, 87],
        list: []
      };
    },
    computed: {
      sum() {
        return this.list.reduce((sum, val) => sum += val, 0)
      }
    }

  };
</script>

<style>
</style>